Heat induced rotating lamp shades are not new. They have existed for many years although they are not considered to be a common or popular household item.
A cone-shaped lamp shade is provided with curved (non-linear) slits having concave sides that are laterally directed and all facing the same direction, i.e., they are unidirectional. The material of the shade outlined by the slits is deflected slightly outwardly from the cone which provides an air opening whereby the deflected material form unidirectional vanes. The cone-shaped lamp shade is suspended over a heat source, e.g., a light bulb. A wire or slim rod having its end projected into the apex of the cone supports the cone. The end of the rod provides a bearing surface as does the apex of the cone so that the cone is free to rotate on the rod end. Heated air rises inside the cone and escapes out the formed openings. In doing so the air pushes against the formed vanes and because the vanes are formed to direct the air in a common direction, the flow of air against the vanes induces rotation of the cone.
As mentioned, the heat-induced rotating lamp shade as generally described has previously been available but has not been a popular household item. There are a number of reasons. A primary object of a lamp is to provide light. The cone-shaped shade blocks much of the light and on occasion it is desirable to remove the shade. Typically the wire or rod support is permanently attached to the lamp base and alternative lamp shades are not adaptable to it. Whereas the rotating lamp shade is a desired novelty, purchasing an entire lamp dedicated to that novelty is not desirable. It may be desirable to transfer the rotating shade from lamp to lamp which is not achievable with prior rotating lamp shades.